Master batch composition and aromatic vinyl-conjugated diene copolymer composition to which said master batch composition is added

A masterbatch composition comprising:

• 30 to 98% by weight of an aromatic vinyl polymer containing at least one aromatic vinyl polymer block, and
• 2 to 70% by weight of a hydrocarbon compound group containing a plurality of hydrocarbon compounds having different numbers of carbon atoms in the range of 12 or more and 60 or less carbon atoms,
• wherein when the hydrocarbon compound group is measured by gas chromatography mass spectrometry (GC-MS) to determine ratios of detected areas of the hydrocarbon compound components having different numbers of carbon atoms to the total peak area of the components having carbon atoms in the range of 12 or more and 60 or less carbon atoms where the total peak area of components having 12 or more and 60 or less carbon atoms is regarded as 100%,
• the total peak area of components having 24 or more and 27 or less carbon atoms is 5% or more,
• the total peak area of components having 27 or more and 30 or less carbon atoms is 5% or more,
• the total peak area of components having 30 or more and 33 or less carbon atoms is 5% or more,
• the total peak area of components having 33 or more and 36 or less carbon atoms is 5% or more, and
• the total peak area of components having 12 or more and 27 or less carbon atoms is 45% or less.